A tertiary ammonium salt ionic liquid, its preparation and use as a space lubricant

Abstract

The application discloses a kind of tertiary ammonium salt ionic liquid and preparation method thereof, it is first with di-n-butylamine and 1-bromoalkane as raw material preparation contains bromine tertiary ammonium salt, then in anhydrous ethanol, the reaction product phosphate of tertiary ammonium salt and potassium hydroxide solid and di(2-ethylhexyl) phosphate ester is reacted at room temperature, obtain light yellow solution and white solid potassium bromide;Solid potassium bromide is removed by filtration, rotary evaporation is removed reaction solvent, then is dried in vacuum, obtain tertiary ammonium salt ionic liquid.The application starts from the molecular structure design of ionic liquid, the prepared ionic liquid does not contain halogen, sulfur and other active elements, will not cause corrosion to spacecraft moving parts, and with good lubricating property, the friction-reducing and anti-wear performance in vacuum harsh environment is especially outstanding, compared with active service aerospace lubricating oil MACs, with more optimal friction-reducing and anti-wear performance, thus can be used as aerospace lubricating oil in lubricating engineering and space field obtains wide application.

Description

Technical Field

[0001] This invention relates to a tertiary ammonium salt ionic liquid and its preparation method, which is mainly used as an aerospace lubricant in the moving mechanisms of spacecraft, belonging to the fields of lubrication engineering and space. Technical Field

[0003] With the rapid development of aerospace technology, extremely high demands have been placed on the long lifespan and reliability of some spacecraft. For example, the International Space Agency is working to establish a permanent manned lunar gateway to realize a human presence on the Moon and ultimately on Mars. This necessitates the comprehensive development of space exploration technologies, including space tribology. In earlier space activities, spacecraft operating times were relatively short. A NASA study shows that many mechanical failures on spacecraft are caused by tribological problems, and a significant proportion of failures in space mechanical components are related to lubrication issues. Whether for satellites, rockets, spacecraft, or space stations, the development of lubrication materials and technologies requires serious attention. Lubrication technology is one of the key technologies for ensuring the safety and reliability of components and extending their service life. To adapt to the development of my country's space science and technology, in-depth systematic research on aerospace lubricants is essential and has broad application prospects.

[0004] Ionic liquids are ionic compounds composed of organic cations and organic / inorganic anions that are liquid near room temperature. They possess unique physicochemical properties such as extremely low saturated vapor pressure, high thermal stability, strong structural designability, and high solubility, making them promising candidates for widespread application as high-performance aerospace lubricants in the space industry. Summary of the Invention

[0005] The purpose of this invention is to provide a tertiary ammonium salt ionic liquid and its preparation method by starting with the molecular structure design of ionic liquids, so as to use it as an aerospace lubricant in the motion mechanism of spacecraft.

[0006] I. Structure and Preparation of Tertiary Ammonium Salt Ionic Liquids The method for preparing tertiary ammonium salt ionic liquid of the present invention includes the following two steps: (1) Preparation of bromine-containing tertiary ammonium salt: Di-n-butylamine and 1-bromoalkanes were used as raw materials and stirred at 70-80℃ for 7-12 hours. The resulting product was a white or pale yellow gel. Vacuum drying was used to remove volatile impurities to obtain the bromine-containing tertiary ammonium salt. Among them, the 1-bromoalkanes were 1-bromooctane and 1-bromododecane; the molar ratio of di-n-butylamine to 1-bromoalkanes was 1:1.

[0007] The reaction formula for synthesizing tertiary ammonium salts containing bromine is as follows: (2) Preparation of tertiary ammonium salt ionic liquid: Potassium hydroxide solid and di(2-ethylhexyl) phosphate were reacted in anhydrous ethanol for 0.5-1 h to obtain a yellow solution of potassium phosphate salt; then, tertiary ammonium salt was added to the yellow solution and stirred at room temperature for 20-24 h to obtain a pale yellow solution and white solid potassium bromide; the solid potassium bromide was removed by filtration, the reaction solvent was removed by rotary evaporation of the filtrate, and then dried in a vacuum drying oven at 70-80℃ for 20-24 h to obtain the tertiary ammonium salt ionic liquid. The molar ratio of potassium hydroxide to di(2-ethylhexyl) phosphate was 1:1; the molar ratio of tertiary ammonium salt to phosphate was 1:1.

[0008] The reaction formula for preparing tertiary ammonium salt ionic liquids is as follows: .

[0009] Figure 1 The tertiary ammonium salt ionic liquid [N] prepared in this invention 448 High-resolution mass spectra of H][DEHP], of which (a) cation mass spectra [C 16 H 36 N] + (b) Anion mass spectrometry [C 16 H 34 PO4] − . Figure 2 The tertiary ammonium salt ionic liquid [N] prepared in this invention 4412 High-resolution mass spectra of H][DEHP], of which (a) cation mass spectra [C 20 H 44 N] + (b) Anion mass spectrometry [C 16 H 34 PO4] − . Figure 1 , 2 High-resolution mass spectrometry analysis shows that the structure of the tertiary ammonium salt ionic liquid of this invention is as follows: In the formula, R1 group is n-hexyl or n-octyl; R2 group is n-butyl.

[0010] II. Lubricating properties of tertiary ammonium salt ionic liquids 1. Tribological property testing in the atmosphere The lubrication performance of the tertiary ammonium salt ionic liquid of this invention as an aerospace lubricant in the atmosphere was investigated using a VFBT-4000 vacuum four-ball testing machine, and compared with that of aerospace lubricants polyalkylated cyclopentanes (MACs). The friction test was conducted for 30 minutes at a temperature of 25°C, a load of 300 N, and a rotation speed of 1450 r / min. Both the upper and lower test balls were GCr15 steel balls. After the friction test, the wear surface of the lower test ball was examined using a scanning electron microscope.

[0011] Figure 3 The curves show the coefficient of friction of tertiary ammonium salt ionic liquids and MACs lubricating oil in the atmosphere as a function of time. Figure 4 The microstructure of wear scars in tertiary ammonium salt ionic liquid and MACs lubricating oil in the atmosphere. Figure 3 , Figure 4 The results show that the tertiary ammonium salt ionic liquid prepared in this invention has better friction-reducing and wear-resistant properties than MACs in the atmosphere, exhibiting good friction-reducing and wear-resistant properties.

[0012] 2. Tribological property testing in high vacuum The lubrication performance of the tertiary ammonium salt ionic liquid of this invention in high vacuum was investigated using a VFBT-4000 vacuum four-ball testing machine, and compared with aerospace lubricating oil polyalkylated cyclopentanes (MACs). The load was set at 300 N, temperature at 25℃, rotation speed at 1450 r / min, and test time at 30 min. Both the upper and lower test balls were GCr15 steel balls. After the friction test, the wear surface of the lower test ball was examined using a scanning electron microscope.

[0013] Figure 5 The curves show the change in the coefficient of friction between tertiary ammonium salt ionic liquid and MACs lubricating oil in high vacuum over time. Figure 6 The image shows the microstructure of the wear scars of tertiary ammonium salt ionic liquid and MACs lubricating oil under high vacuum using SEM. Figure 5 , Figure 6 The results show that the tertiary ammonium salt ionic liquid prepared in this invention can eliminate the transient high friction phenomenon that occurs in MACs lubricating oil in high vacuum, and exhibits excellent friction reduction and anti-wear performance.

[0014] In summary, this invention first prepares a bromine-containing tertiary ammonium salt from di-n-butylamine and 1-bromoalkane. Then, in anhydrous ethanol, the tertiary ammonium salt reacts with solid potassium hydroxide and the phosphate product (di(2-ethylhexyl) phosphate) at room temperature to obtain a pale yellow solution and a white solid potassium bromide. The solid potassium bromide is removed by filtration, the reaction solvent is removed by rotary evaporation, and then the solution is dried under vacuum to obtain the tertiary ammonium salt ionic liquid. This invention focuses on the molecular structure design of the ionic liquid. The prepared ionic liquid is free of halogens, sulfur, and other active elements, and will not corrode moving parts of spacecraft. It also exhibits excellent lubrication properties, with particularly outstanding friction-reducing and anti-wear performance under harsh vacuum conditions. Compared with existing aerospace lubricants (MACs), it has superior friction-reducing and anti-wear properties, and therefore can be widely used as an aerospace lubricant in lubrication engineering and the space industry. Attached Figure Description

[0015] Figure 1 The tertiary ammonium salt ionic liquid [N] prepared in Example 1 of this invention 448 High-resolution mass spectra of H][DEHP]: (a) Cation mass spectrum [C 16 H 36 N] + (b) Anion mass spectrometry [C 16 H 34 PO4] − .

[0016] Figure 2 The tertiary ammonium salt ionic liquid [N] prepared in Example 1 of this invention 4412 High-resolution mass spectra of H][DEHP]: (a) Cation mass spectrum [C 20 H 44 N] + (b) Anion mass spectrometry [C 16 H 34 PO4] − .

[0017] Figure 3 The curve showing the change of the friction coefficient of the tertiary ammonium salt ionic liquid of this invention with MACs in the atmosphere over time.

[0018] Figure 4 This is a SEM image of the wear scar microstructure of the tertiary ammonium salt ionic liquid and MACs in the atmosphere.

[0019] Figure 5 The curve showing the change of the friction coefficient between the tertiary ammonium salt ionic liquid of this invention and MACs in high vacuum over time.

[0020] Figure 6 This is a SEM image showing the microstructure of the wear scars of the tertiary ammonium salt ionic liquid and MACs under high vacuum. Detailed Implementation

[0021] The preparation and lubrication properties of the tertiary ammonium salt ionic liquid of the present invention will be further illustrated below through specific embodiments.

[0022] Example 1 (1) Add 12.92 g of di-n-butylamine to a round-bottom flask, place the flask in an oil bath, start stirring and heat to 50°C; add 19.31 g of 1-bromo-n-octane dropwise, and after the addition is complete, heat to 70°C and stir for 7 h to ensure complete reaction. The resulting product is a white gel. Dry the volatile impurities in the product in a vacuum drying oven to obtain a bromine-containing tertiary ammonium salt, denoted as [N... 448 H]Br; (2) Take 5.61 g of potassium hydroxide solid and 32.24 g of di(2-ethylhexyl) phosphate, react in 50 mL of anhydrous ethanol for 1 h to obtain a yellow solution of potassium phosphate salt; then add 32.23 g of [N] to the yellow solution. 448 [H]Br, stirred at room temperature for 20 h, yielded a pale yellow solution and a white solid potassium bromide; after multiple filtrations to remove the pure potassium bromide solid, the filtrate was rotary evaporated to remove anhydrous ethanol and water, and finally dried in a vacuum drying oven at 70 °C for 20 h to obtain a tertiary ammonium salt ionic liquid, denoted as [N]Br. 448 H][DEHP]. [N] 448 The characterization results of H][DEHP are as follows: Figure 1 According to measurements, [N] 448 The lubrication properties of H][DEHP in atmosphere and high vacuum are shown in Tables 1 and 2.

[0023] Example 2 (1) Add 12.92 g of di-n-butylamine to a round-bottom flask, place the flask in an oil bath, start stirring and heat to 60°C. Add 24.92 g of 1-bromododecane dropwise. After the addition is complete, heat to 80°C and stir for 12 h to ensure complete reaction. The resulting product is a pale yellow gel. Dry the product in a vacuum drying oven to remove volatile impurities, and you will get a bromine-containing tertiary ammonium salt, denoted as [N]. 4412 H]Br.

[0024] (2) Take 5.61 g of potassium hydroxide solid and react it with 32.24 g of di(2-ethylhexyl) phosphate in 60 mL of anhydrous ethanol for 1 h to obtain a yellow solution of potassium phosphate salt; then add 37.85 g of [N] to the yellow solution. 4412 [H]Br, stirred at room temperature for 24 h, yielded a pale yellow solution and a white solid potassium bromide; the potassium bromide solid was then removed by multiple filtrations, and the filtrate was evaporated by rotary evaporation to remove anhydrous ethanol and water; finally, it was dried in a vacuum drying oven at 80 °C for 24 h to obtain a tertiary ammonium salt ionic liquid, denoted as [N]Br.4412 H][DEHP]. [N] 4412 The characterization results of H][DEHP are as follows: Figure 2 According to measurements, [N] 4412 The lubrication properties of H][DEHP in atmosphere and high vacuum are shown in Tables 1 and 2, respectively. .

Claims

1. A tertiary ammonium salt ionic liquid, the structural formula of which is as follows: In the formula, R1 group is n-octyl or dodecyl; R2 group is n-butyl.

2. The method for preparing a tertiary ammonium salt ionic liquid as described in claim 1, comprising the following two steps: (1) Preparation of bromine-containing tertiary ammonium salt: using di-n-butylamine and 1-bromoalkanes as raw materials, the reaction is stirred at 70-80℃ for 7-12 hours, and the product is a white or pale yellow gel. After vacuum drying to remove volatile impurities, bromine-containing tertiary ammonium salt is obtained; the 1-bromoalkanes are 1-bromooctane and 1-bromododecane. (2) Preparation of tertiary ammonium salt ionic liquid: potassium hydroxide solid and di(2-ethylhexyl) phosphate were reacted in anhydrous ethanol for 0.5-1 h to obtain a yellow solution of potassium phosphate salt; then tertiary ammonium salt was added to the yellow solution and stirred at room temperature for 20-24 h to obtain a pale yellow solution and white solid potassium bromide; the solid potassium bromide was removed by filtration, the reaction solvent was removed by rotary evaporation of the filtrate, and then dried in a vacuum drying oven at 70-80℃ for 20-24 h to obtain tertiary ammonium salt ionic liquid.

3. The method for preparing a tertiary ammonium salt ionic liquid as described in claim 2, characterized in that: In step (1), the molar ratio of di-n-butylamine to 1-bromoalkane is 1:

1.

4. The method for preparing a tertiary ammonium salt ionic liquid as described in claim 2, characterized in that: In step (2), the molar ratio of potassium hydroxide to di(2-ethylhexyl) phosphate is 1:

1.

5. The method for preparing a tertiary ammonium salt ionic liquid as described in claim 2, characterized in that: In step (2), the molar ratio of tertiary ammonium salt to phosphate is 1:

1.

6. The application of the tertiary ammonium salt ionic liquid as described in claim 1 as an aerospace lubricant.

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